Surface Modification Functionalized Carbon Dots.

Carbon dots (CDs) smaller than 10 nm constitute a new type of fluorescent carbon-based nanomaterial. They have attracted much attention owing to their unique structures and excellent photoelectric properties. Primitive CDs usually comprise carbon and oxygen and are synthesized in one step from various natural products or synthetic organic compounds, usually via microwave or hydrothermal methods. However, the uniformity of surface functional groups often make CDs lack the diversity of active sites required for specific applications. Therefore, the functionalization of CDs by specific groups is a powerful strategy for improving their photophysical and photochemical properties. This paper reviews surface modification strategies to overcome these shortcomings. Functionalizing CDs using covalent or non-covalent modification can give them unique properties and broaden their applicability.

Effect of Stoichiometry on Nanomagnetite Sulfidation.

Magnetite (Mt) has long been regarded as a stable phase with a low reactivity toward dissolved sulfide, but natural Mt with varying stoichiometries (the structural Fe(II)/Fe(III) ratio, xstru) might exhibit distinct reactivities in sulfidation. How Mt stoichiometry affects its sulfidation processes and products remains unknown. Here, we demonstrate that xstru is a master variable controlling the rates and extents of sulfide oxidation by magnetite nanoparticles (11 ± 2 nm). At pH = 7.0-8.0 and the initial Fe/S molar ratio of 10-50, the partially oxidized magnetite (xstru = 0.19-0.43) can oxidize dissolved sulfide to elemental sulfur (S0), but only surface adsorption of sulfide, without interfacial electron transfer (IET), occurs on the nearly stoichiometric magnetite (xstru = 0.47). The higher initial rate and extent of sulfide oxidation and S0 production are observed with the more oxidized magnetite that has the higher electron-accepting capability from surface-complexed sulfide (S(-II)(s)). The FeS clusters formed from magnetite sulfidation can be oxidized by the most oxidized magnetite with xstru = 0.19 but not by other magnetite particles. A linear relationship between the Gibbs free energy of reaction and the surface area-normalized initial rate of sulfide oxidation is observed in all experiments under the different conditions, suggesting the S(-II)(s)-magnetite IET dominates magnetite sulfidation at high Fe/S molar ratios and near-neutral pH.

Occurrence rates and risk factors of in-hospital venous thromboembolism, major bleeding, and death in patients receiving fondaparinux after orthopedic surgery or trauma surgery.

AIM: Fondaparinux is a synthetic anticoagulant that inhibits thrombosis by suppressing factor Xa. The efficacy of fondaparinux for orthopedic surgeries has been revealed by several foreign studies; however, relevant evidence in Chinese patients is lacking. This study intended to investigate the occurrence rate and risk factors of in-hospital venous thromboembolism (VTE), major bleeding, and death in patients receiving fondaparinux after orthopedic surgery or trauma surgery. METHODS: Totally, 1258 patients who received fondaparinux after orthopedic surgery or trauma surgery were retrospectively enrolled. Meanwhile, in-hospital VTE, major bleeding, and death were obtained for assessment. Besides, adverse events were recorded. RESULTS: The occurrence rates of in-hospital VTE, major bleeding, and death were 2.5%, 21.8%, and 0.0%, respectively. The multivariate logistic regression analysis revealed that only age (> 60 years vs. ≤ 60 years) (odd ratios (OR) = 3.380, P = 0.013) was independently correlated with increased risk of in-hospital VTE. Additionally, osteoarthritis diagnosis (OR = 3.826, P < 0.001), femoral head necrosis diagnosis (OR = 1.809, P = 0.034), hip replacement (vs. internal fracture fixation) (OR = 2.199, P = 0.007), knee replacement (vs. internal fracture fixation) (OR = 2.781, P = 0.002), and serum creatinine (abnormal vs. normal) (OR = 1.677, P = 0.012) were independently linked to a higher risk of in-hospital major bleeding. Moreover, the common adverse events included pain (56.6%), wound bleeding (23.0%), increased drainage (5.2%), etc. CONCLUSION: Fondaparinux realizes low occurrence rates of in-hospital VTE and major bleeding with tolerable adverse events in patients receiving orthopedic surgery or trauma surgery.

Ligand-Triggered Self-Assembly of Flexible Carbon Dot Nanoribbons for Optoelectronic Memristor Devices and Neuromorphic Computing.

Carbon dots (CDs) are widely utilized in sensing, energy storage, and catalysis due to their excellent optical, electrical and semiconducting properties. However, attempts to optimize their optoelectronic performance through high-order manipulation have met with little success to date. In this study, through efficient packing of individual CDs in two-dimensions, the synthesis of flexible CDs ribbons is demonstrated technically. Electron microscopies and molecular dynamics simulations, show the assembly of CDs into ribbons results from the tripartite balance of π-π attractions, hydrogen bonding, and halogen bonding forces provided by the superficial ligands. The obtained ribbons are flexible and show excellent stability against UV irradiation and heating. CDs ribbons offer outstanding performance as active layer material in transparent flexible memristors, with the developed devices providing excellent data storage, retention capabilities, and fast optoelectronic responses. A memristor device with a thickness of 8 µm shows good data retention capability even after 104 cycles of bending. Furthermore, the device functions effectively as a neuromorphic computing system with integrated storage and computation capabilities, with the response speed of the device being less than 5.5 ns. These properties create an optoelectronic memristor with rapid Chinese character learning capability. This work lays the foundation for wearable artificial intelligence.

Solid-state Fluorescence from Carbon Dots Widely Tunable from Blue to Deep Red through Surface Ligand Modulation.

Carbon dots (CDs) find widespread attention due to their remarkable fluorescent and electronic properties. However, aggregation-caused quenching currently limits the application of CDs in colored displays. The construction of CDs with color-tunable solid-state fluorescence (SSF) is rarely reported, since the preparation of SSF CDs is technically challenging. Herein, through surface ligand modulation, SSF CDs with an emission-color span of almost 300 nm (from blue to deep red) were obtained. In-depth structure-property studies reveal that intra- and inter-molecular hydrogen-bonding inside SSF CDs provokes the emission properties in the aggregated state. Photodynamic characterizations demonstrate emission wavelengths can be switched smoothly by deliberately altering conjugation ability between substituent ligands and CDs core. Three-dimensional printing patterning is used to create a range of emissive objects, demonstrating the commercial potential for use in optical lamps.

Effects of high viscosity bone cement percutaneous vertebroplasty on pain, bone specific alkaline phosphatase, Type-I collage cross-linked-telopeptide and Boneglaprotein levels in patients with osteoporotic vertebral compression fractures.

Objectives: To investigate the effects of percutaneous vertebroplasty with high viscosity bone cement on pain and the levels of bone specific alkaline phosphatase (BALP), Type-I collagen cross-linked telopeptide (CTX) and serum osteocalcin (BGP) in patients with osteoporotic vertebral compression fractures. Methods: The medical records of patients with osteoporotic vertebral compression fractures treated in our hospital from February 2020 to February 2021 were selected after retrospective analysis. Patients (43) who received low viscosity bone cement percutaneous vertebroplasty comprised Group-I, and patients (56) who received high viscosity bone cement percutaneous vertebroplasty, comprised Group-II of the study. The occurrence of bone cement leakage, pain (VAS scores), BALP, CTX and BGP were compared and analyzed between the two groups. Results: The incidence of bone cement leakage in Group-II was 16.28%, lower than 3.57% in Group-I (P<0.05). The visual analogue scale (VAS) scores of patients in Group-II were lower than those in Group-I at one and three months after the surgery (P<0.05). The levels of BALP and BGP in Group-II were higher than those in Group-I three months after the surgery (P<0.05), and CTX was lower than those in Group-I (P<0.05). Conclusions: Percutaneous vertebroplasty with high viscosity bone cement in the treatment of osteoporotic vertebral compression fractures can reduce the incidence of bone cement leakage and help to further reduce pain and improve bone metabolism.

The comparison of clinical effect, knee function, prognosis of double plate fixation and locking plate internal fixation for tibial plateau fractures.

Objectives: The purpose of this study was to investigate the clinical effect, knee function improvement and prognosis of double plate internal fixation and locking plate internal fixation in the treatment of tibial plateau fractures. Methods: Clinical data from 96 tibial plateau fracture patients treated at our hospital were analyzed retrospectively. Of these, 46 had been treated using locking plate internal fixation and 50 were treated with double T-shaped plate fixation. Clinically related indices, Hospital for Special Surgery (HSS) score of knee function, and ability of daily living (ADL) score were evaluated during postoperative follow-up. Results: No significant differences were observed in pre-operative patient characteristics in both groups. Healing time, time to weight-bearing, tibial plateau angle (TPA) and lateral posterior angle (PA) were all superior in the locking plate fixation group compared to the double plate fixation group. At three months post-operative visit, range of motion, knee function, flexion deformity, muscle strength, pain, and stability metrics were all superior in the locking plate fixation group compared to the double plate fixation group. ADL scores were also higher in the locking plate fixation group than in the double plate fixation group at three and six months follow-up. Conclusions: The clinical effect, knee function improvement and prognosis of locking plate internal fixation in the treatment of tibial plateau fractures are better than those of double plate fixation.

The effect of platelet rich plasma combined with celecoxib on knee function and pain in patients with knee osteoarthritis.

Objectives: To analyze the immediate effect of platelet rich plasma, combined with celecoxib, on knee function and pain in patients with knee osteoarthritis. Methods: The clinical data of 86 patients with knee osteoarthritis, treated in our hospital from January 2019 to January 2021, were analyzed retrospectively. According to the treatment records, patients were divided into a control group (n = 43, celecoxib) and a treatment group (n = 43, platelet rich plasma + celecoxib). The knee function, pain and clinical effect in the two groups were compared and analyzed using the Hospital for Special Surgery (HSS) knee score and the visual analog scale (VAS). Results: The treatment group had a higher HSS score, and a lower VAS score compared to the control group (P<0.05). The clinical efficacy in the treatment group was higher than that in the control group (95.35% and 72.09% respectively, P<0.05). Conclusions: Platelet rich plasma combined with celecoxib can promote the recovery of knee function and reduce pain in patients with knee osteoarthritis. This treatment combination also has a high immediate clinical effectiveness but needs further evaluation to find out the long term effects.

Understanding the Importance of Labile Fe(III) during Fe(II)-Catalyzed Transformation of Metastable Iron Oxyhydroxides.

Transformation of metastable Fe(III) oxyhydroxides is a prominent process in natural environments and can be significantly accelerated by the coexisting aqueous Fe(II) (Fe(II)aq). Recent evidence points to the solution mass transfer of labile Fe(III) (Fe(III)labile) as the primary intermediate species of general importance. However, a mechanistic aspect that remains unclear is the dependence of phase outcomes on the identity of the metastable Fe(III) oxyhydroxide precursor. Here, we compared the coupled evolution of Fe(II) species, solid phases, and Fe(III)labile throughout the Fe(II)-catalyzed transformation of lepidocrocite (Lp) versus ferrihydrite (Fh) at equal Fe(III) mass loadings with 0.2-1.0 mM Fe(II)aq at pH = 7.0. Similar to Fh, the conversion of Lp to product phases occurs by a dissolution-reprecipitation mechanism mediated by Fe(III)labile that seeds the nucleation of products. Though for Fh we observed a transformation to goethite (Gt), accompanied by the transient emergence and decline of Lp, for initial Lp we observed magnetite (Mt) as the main product. A linear correlation between the formation rate of Mt and the effective supersaturation in terms of Fe(III)labile concentration shows that Fe(II)-induced transformation of Lp into Mt is governed by the classical nucleation theory. When Lp is replaced by equimolar Gt, Mt formation is suppressed by opening a lower barrier pathway to Gt by heterogeneous nucleation and growth on the added Gt seeds. The collective findings add to the mechanistic understanding of factors governing phase selections that impact iron bioavailability, system redox potential, and the fate and transport of coupled elements.

LncRNA ARFRP1 knockdown inhibits LPS-induced the injury of chondrocytes by regulation of NF-κB pathway through modulating miR-15a-5p/TLR4 axis.

AIMS: Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been reported as the important regulators in osteoarthritis (OA). However, the detailed mechanism is implicated. The aim of this study is to reveal the functional mechanism of lncRNA ARFRP1 and miR-15a-5p in osteoarthritis. MATERIALS AND METHODS: The expression level of genes was detected by quantitative real time polymerase chain reaction (qRT-PCR) or western blot assay. Cell Counting Kit-8 (CCK-8) was used to assess cell viability. Cell apoptosis rate was analyzed by flow cytometry analysis. Furthermore, Enzyme-linked immunosorbent assay (ELISA) was performed to measure tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1ß contents. The interaction between miR-15a-5p and ARFRP1 or Toll-like receptor 4 (TLR4) was predicted by miRcode or PITA, and then confirmed by the dual luciferase reporter assay or pull down assay. Besides, NF-κB-driven luciferase activity was determined using NF-κB luciferase reporter assay. KEY FINDINGS: ARFRP1 and TLR4 levels were increased and miR-15a-5p level was decreased in OA cartilage tissues and lipopolysaccharides (LPS)-induced chondrocytes. ARFRP1 knockdown inhibited LPS-induced the injury of chondrocytes. Interestingly, miR-15a-5p downregulated by ARFRP1 negatively modulated TLR4 expression through interaction. ARFRP1 mediated LPS-induced the injury of chondrocytes via regulating miR-15a-5p/TLR4 axis. Furthermore, ARFRP1 exerted function by modulation of NF-κB pathway. SIGNIFICANCE: Our findings confirmed that ARFRP1 mediated LPS-induced the injury of chondrocytes through regulating NF-κB pathway by modulation of miR-15a-5p/TLR4 axis, providing theoretical basis for the treatment of OA patients.

Ectopic chondrogenesis of nude mouse induced by nano gene delivery enhanced tissue engineering technology.

Background: Many techniques and methods have been used clinically to relieve pain from cartilage repair, but the long-term effect is still unsatisfactory. Purpose: The objective of this study was to form an artificial chondroid tissue gene enhanced tissue engineering system to repair cartilage defects via nanosized liposomes. Methods: Cationic nanosized liposomes were prepared and characterized using transmission electron microscope (TEM) and dynamic laser light scattering (DLS). The rat mesenchymal stem cells (rMSCs) were isolated, cultivated, and induced by SRY (Sex-Determining Region Y)-Box 9 (Sox9) via cationic nanosized liposomes. The induced rMSCs were mixed with a thermo-sensitive chitosan hydrogel and subcutaneously injected into the nude mice. Finally, the newly-formed chondroid tissue obtained in the injection parts, and the transparent parts were detected by HE, collagen II, and safranin O. Results: It was found that the presently prepared cationic nanosized liposomes had the diameter of 85.76±3.48 nm and the zeta potential of 15.76±2.1 mV. The isolated rMSCs proliferation was fibroblast-like, with a cultivated confluence of 90% confluence in 5-8 days, and stained positive for CD29 and CD44 while negative for CD34 and CD45. After transfection with cationic nanosized liposomes, we observed changes of cellular morphology and a higher expression of SOX9 compared with control groups, which indicated that rMSCs could differentiate into chondrocyte in vitro. By mixing transfected rMSCs with the thermo-sensitive hydrogel of chitosan in nude mice, chondroid tissue was successfully obtained, demonstrating that rMSCs can differentiate into chondrogenic cells in vivo. Conclusion: This study explored new ways to improve the quality of tissue engineered cartilage, thus accelerating clinical transformation and reducing patient pain.